exam 2 Flashcards
What are the five major function of the skeletal system?
Support- structural support and framework for attachment of soft tissues and organs.
Storage- maintains normal concentrations of calcium and phosphorus ion, stores energy reserves in the form of lipid in yellow marrow
Blood cell production- (hematopoiesis) red, white, and other blood cells elements produce within red marrow.
Protection- protect soft tissues and organs.
Movement- skeletal muscles attached to bones by tendons, use as a levers to move.
Calcium (calcium phosphate)
- most abundant mineral in the body.
- accounts for almost 2/3 of the wight of bone
four general shapes of bones
- Long bones, longer than wide (femur)
- Short bones, cube shape, contain mostly spongy bone. (carpal)
- Flat bones, thin, flattened usually cured. (parietal, mandible, clavicles)
- Irregular bones, complex do not fit into any other category(vertebra)
Sesamoid bones
-short bone forms within tendons. Patella
Diaphysis
- central shaft of the long bone.
- surrounds central marrow cavity also know as yellow marrow cavity or medullary cavity.
- serves primarily as storage area for adipose tissue
epiphyses
- expanded portions at each end of the long bone.
- covered by articular cartilage (hyaline), and articulates with adjacent bones
Cancellous bone
- SPONGY bone, resembles a network of bony rods, struts separated by space.
- fills epiphyses
Trabecular bone
- SPONGY bone, resembles a network of bony rods, struts separated by space.
- fills epiphyses
Compact bone
- compact bone (dense bone)
- forms diaphysis
Red marrow
- forms blood cells
- confined to cavities in spongy bone of flat bones and epiphyses of long
Epiphyseal plates
- allow the lengthwise growth of a long
bone. - growth plate
periosteum
- outer surface of a bone.
- fibers of tendons and ligaments intermingle with periosteum and attach skeletal muscle to bone and one bone to another
Perforating fibers or Sharpey’s fibers
connective tissue fibers,secure the periosteum to the underlying bone.
periosteum
isolates the bone from surrounding tissues, provides a route for circulatory and nervous supplies, and participates in bone growth and repair.
osteocytes
bone cells
lacunae
small pockets, house osteocytes
lamellae
- narrow sheets of calcified matrix where lacunae is located
- cylindrical and oriented parallel to the long axis of the central canal.
canaliculi
- Small channels, radiate through the matrix, and interconnect lacunae, and link them to nearby blood vessels.
- nutrients and waste products from osteocytes deffuse through extracellular fluid that surrounds these cells.
osteon
or Haversian system, basic functional and structural unit of compact bone
Haversian system
basic functional and structural unit of compact bone
Haversian canal
-Central canal,contains nerves, blood vessels, and lymphatics.
Compact Bone
- covers bone surfaces everywhere, EXEPT inside joint capsules, where articular hyaline
cartilages protect opposing surfaces. - usually found where stresses come from a
limited range of directions.
Spongy Bone
- has a different lamellar arrangement and no osteons
- instead, the lamellae form rods or plates called trabeculae.
- much lighter than compact bones and found where are not heavily stressed.
Cells in Osseous Tissue
Osteocytes
osteoclasts
osteoblasts
Osteocytes
- mature bones cells
- maintain normal bone structure by recycling the calcium in bony matrix
- assisting in repairs
Osteoclasts
- dissolve the bony matrix by secreting acids and enzymes in order to release the stored minerals through OSTEOLYSIS (resorption).
- helps regulate calcium and phosphate concentrations in body fluids.
- REMOVING MATRIX
- after epiphyseal cartilages have closed normaly activities are balanced, as one forms another is destroyed.
Osteoblasts
- responsible for the production of new bone (osteogenesis).
- produce new bone matrix and promote the deposition of calcium salts in the organic matrix.
- ADDING TO IT
osteogenesis
production of new bone
metaphysis
- narrow portion of the long bone between the epiphysis and diaphysis.
- contains the growth plate
ossification
- process of replacing other tissues with bone.
- During development, cartilage or other connective tissues are replaced by bone
calcification
deposition of calcium salts, occurs during ossification, but it can also occur in tissues other than bone.
articular hyaline
cartilages
inside joint capsules, protects opposing surfaces
endochondral ossification
- Most of the bones of the body are formed through.
- bone replaces existing hyaline cartilage, which develops first
two major forms of ossification
- Intramembranous Ossification
- In membrane - Endochondral Ossification
- inside cartilage
intramembranous ossification,
-bone develops within
sheets or membranes of connective tissue.
-The flat bones of the skull, the lower jaw (mandible), and the collarbones (clavicles) form this way.
Bone formation first occurs at
shaft surface
articular cartilage
- thin cap of the original cartilage model remains exposed to the joint cavity.
- its a smooth white tissues that covers bone ends and forms joints.
- allows bones to glide over each orther.
- articular hyaline
epiphyseal line
In adults, the former location of the epiphyseal cartilage
epiphyseal closure
The end of epiphyseal growth
appositional growth
-While the bone elongates, its diameter also enlarges at
its outer surface.
-occurs as cells of the periosteum develop into
osteoblasts, and produce additional bony matrix.
a typical human body contains how much calcium?
- 2 1/4 to 4 1/2 pounds
- 99% is deposited in the skeleton
Vitamin D3
- after processed in the liver, the kidneys convert a derivative of this vitamin into
calcitriol, which is a hormone that stimulates the
absorption of calcium and phosphate ions in the
digestive tract.,
calcitriol
stimulates the
absorption of calcium and phosphate ions in the
digestive tract.
Normal bone growth and maintenance cannot occurwithout a reliable source of minerals, especially?
calcium salts
Most abundant mineral in the human body?
calcium
parathyroid hormone (PTH)
-When blood calcium levels drop below homeostatic levels, the parathyroid glands are stimulated to release parathyroid hormone (PTH) - PTH activates osteoclasts to break down bone matrix, and release calcium ions into the blood. (negative feedback)
calcitonin
When blood calcium levels are too high, the thyroid glandreleases calcitonin, which causes calcium to be
deposited in bone matrix as hard calcium salts.
what helps maintain calcium homeostasis in body fluids
The skeleton by providing calcium reserves
what two controlling mechanisms work together?
calcium regulation (uptake & release), and bone remodeling
what determines where bone matrix is to be
broken down or formed?
The stresses of muscle pull and gravity
osteopenia.
Inadequate ossification
Osteoporosis
Produces a reduction in
bone mass great enough to compromise normal
function.
what are the four general types of skeletal and joint injuries?
Sprain
Subluxation
Dislocation
Fracture
Sprain
injury that stretches or tears one or more
ligaments within a joint.
Subluxation
also called a partial dislocation, is a partial
displacement of a bone end, from its position within a joint
capsule.
Dislocation
complete displacement of bone ends from their
normal position within a joint. This injury is at risk of
entrapping, compressing or tearing nearby blood vessels and
nerves.
Fracture
injury that disrupts the structural integrity of
a bone.
fracture hematoma
- large blood clot
- forms after a break and extensive bleeding around the fracture
internal callus
forms, as a network of spongy bone
unites the inner edges after a break
external callus
cartilage and bone stabilizes the outer edges after a break
The cartilage of the external callus is replaced by?
bone, and struts of spongy bone unite the broken ends.
what initially marks the location of the fracture?
Swelling
closed fracture
the skin is not broken, and there is no communication between the fracture site and the environment.
open fracture
the skin is broken and a
communication exists between the fracture site and
the environment.
- usually taken to the operating room,
where the fracture site is exposed, cleansed, and
irrigated to prevent infection
greenstick fracture
(seen almost exclusively
in children) is caused when an angular force is
applied to a long bone, resulting in bowing of
one side of the cortex, and fracture of the
other side of the cortex